package com.st.vmall.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;

public class ValidateCodeUtil {

	private static Random random = new Random();
    private static String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串
    
    private static int width = 80;//图片宽
    private static int height = 26;//图片高
    private static int lineSize = 40;//干扰线数量
    private static int stringNum = 4;//随机产生字符数量
	
	public static String createValidateCode(HttpServletResponse response) {
		
		String randStr = createRandomString();
		
		//BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
        //产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman",Font.ROMAN_BASELINE,18));
        g.setColor(getRandColor(160, 200));
        //绘制干扰线
        for(int i=0;i<=lineSize;i++){
            drowLine(g);
        }
        
        // 绘制字符串
        for (int i=0; i<randStr.length(); i++) {
        	drowChar(g, randStr.charAt(i), i);
        }

        g.dispose();
        
        try {
        	//将内存中的图片通过流动形式输出到客户端
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }

        return randStr;
	}
	
	private static void drowChar(Graphics g, char c, int i) {
		g.setFont(getFont());
		g.setColor(new Color(random.nextInt(101),random.nextInt(111),random.nextInt(121)));
		g.translate(random.nextInt(3), random.nextInt(3));
		g.drawString(c+"", 13*i, 16);
	}
	
	/*
     * 获得字体
     */
    private static Font getFont(){
        return new Font("Fixedsys",Font.CENTER_BASELINE,18);
    }

	private static String createRandomString() {
		String str = "";
		
		for (int i=0; i<stringNum; i++) {
			int index = random.nextInt(randString.length());
			char c = randString.charAt(index);
		
			str += c;
		}
		
		return str;
	}
	
	 /*
     * 获得颜色
     */
    private static Color getRandColor(int fc,int bc){
        if(fc > 255)
            fc = 255;
        if(bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc-fc-16);
        int g = fc + random.nextInt(bc-fc-14);
        int b = fc + random.nextInt(bc-fc-18);
        return new Color(r,g,b);
    }
    
    /*
     * 绘制干扰线
     */
    private static void drowLine(Graphics g){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x+xl, y+yl);
    }

}
